title: Physiological and performance responses to a training camp in the heat in professional Australian football players.
abstract: OBJECTIVE
  To examine the physiological and performance responses to a heat-acclimatization camp in highly trained professional team-sport athletes.
  
  
  METHODS
  Eighteen male Australian Rules Football players trained for 2 wk in hot ambient conditions (31-33°C, humidity 34-50%). Players performed a laboratory-based heat-response test (24-min walk + 24 min seated; 44°C), a YoYo Intermittent Recovery Level 2 Test (YoYoIR2; indoor, temperate environment, 23°C) and standardized training drills (STD; outdoor, hot environment, 32°C) at the beginning and end of the camp.
  
  
  RESULTS
  The heat-response test showed partial heat acclimatization (eg, a decrease in skin temperature, heart rate, and sweat sodium concentration, P < .05). In addition, plasma volume (PV, CO rebreathing, +2.68 [0.83; 4.53] mL/kg) and distance covered during both the YoYoIR2 (+311 [260; 361] m) and the STD (+45.6 [13.9; 77.4] m) increased postcamp (P < .01). None of the performance changes showed clear correlations with PV changes (r < .24), but the improvements in running STD distance in hot environment were correlated with changes in hematocrit during the heat-response test (r = -.52, 90%CI [-.77; -.12]). There was no clear correlation between the performance improvements in temperate and hot ambient conditions (r < .26).
  
  
  CONCLUSIONS
  Running performance in both hot and temperate environments was improved after a football training camp in hot ambient conditions that stimulated heat acclimatization. However, physiological and performance responses were highly individual, and the absence of correlations between physical-performance improvements in hot and temperate environments suggests that their physiological basis might differ.
authors.affiliation: Aspetar, Qatar Orthopaedic and Sports Medicine Hospital, Research and Education Center, Doha, Qatar.
authors.forename: Sebastien
authors.initials: S
authors.lastname: Racinais
authors.forename: Martin
authors.initials: M
authors.lastname: Buchheit
authors.forename: Johann
authors.initials: J
authors.lastname: Bilsborough
authors.forename: Pitre C
authors.initials: PC
authors.lastname: Bourdon
authors.forename: Justin
authors.initials: J
authors.lastname: Cordy
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Coutts
mesh_terms: D000064:Acclimatization; D001315:Australia; D005080:Exercise Test; D006339:Heart Rate; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D008297:Male; D009048:Motor Skills; D064797:Physical Conditioning, Human / Q000379:methods*; D010807:Physical Endurance; D010953:Plasma Volume; D012119:Respiration; D012420:Running; D012881:Skin Temperature; D012964:Sodium / Q000378:metabolism; D013177:Sports; D013542:Sweat / Q000378:metabolism; D013546:Sweating; D013647:Task Performance and Analysis; D013997:Time Factors; D055815:Young Adult
chemical_list: D012964:Sodium